The Al3+ sensor, 7‐nitrobenz‐2‐oxa‐1, 3‐diazole (NBD) derived fluorescent probe 2‐((E)‐(4‐(phenylamino)benzo[c][1,2,5]oxadiazol‐7‐ylimino)methyl) phenol (3) was synthesized and characterized by various spectral methods and crystallography. The compound (3) exhibits dual channel (fluorometric and colorimetric) sensor behaviour. It has high selectivity for Al3+ detection, produced significant fluorescence enhancement in the presence of Al3+ ion. It shows ‘‘turn off–on’’ fluorescent responses toward Al3+ in semi aqueous medium. Here, the correlative the properties of a photo sensor (NBD based schiff‘s base 3 with normal NBD derivatives 1, 2) towards Al3+ was studied. The solvent effect and cation sensing properties were investigated from ultraviolet spectroscopy and fluorescence spectroscopic methods. The facile synthetic probe 3 will alternative and open new opportunities in bio‐imaging of Al3+ in various cell lines. This will certainly be helpful in understanding the fundamental mechanism of aluminium‐induced human diseases.

The fluorescent probes 7‐nitro‐N‐phenylbenzo[c][1,2,5]oxadiazol‐4‐amine (1), and 4‐((7‐nitrobenzo[c][1,2,5]oxadiazol‐4‐yl)amino)benzonitrile (2) were synthesised for the detection of cyanide ion (CN−). A new correlative approach with nitrobenzoxadiazole (NBD)‐based probes to detecting CN− by the Donor‐Acceptor D‐A (1) and Acceptor‐Donor‐Acceptor (A‐D‐A) (2) with the aid of DFT calculations are reported. Given their design features, these NBD probes 1 and 2 provide useful insights into the dual‐channel (fluorometric and colorimetric) sensor activity with good selectivity for CN− detection, considerable fluorescence amplification in the presence of CN− ion, and the desirable “Off–on” fluorescent responses toward CN− in the semi‐aqueous medium. The photophysical studies confirmed the A‐D‐A type molecule has a detection limit 0.163 μM for CN− sensing, which is lower than the WHO′s cyanide in water permitted limit. The simple synthetic probes 1 and 2 will offer up new possibilities for industrial effluent CN− detection and bio‐imaging of CN− in a variety of cell lines. This will undoubtedly aid in the understanding of the basic mechanism of CN− poisoning in the bloodstream.